This invention relates to a stator for an electric machine which includes a tubular unslotted ferromagnetic flux collector ring, and stator windings formed by a number of winding coils associated with the flux collector ring, wherein each of the winding coils has at least two legs which extend substantially axially along the inner cylindrical surface of the flux collector ring.
A problem concerned with previous electric machines of the above type is a relatively small effective space available for the winding coil wires in relation to the total cross sectional area of the windings within the flux collector ring. This means a relatively low efficiency of the machine.
One prior art method for arranging the stator windings inside a flux collector ring is described in EP 0 225 132 and comprises mounting of the winding coils on a support structure of a non-magnetisable, non-conductive material and insertion of the support structure and the windings together into the flux collector ring. In this known machine, the winding support structure takes a lot of space and reduces the effective space available for the winding coil wires.
Another prior art method for building electric machine stators, see for instance EP 0 193 929, comprises the measures of locating the winding legs by their end by using threads or tape, and then introducing them together with a fiberglass sleeve into the flux collector ring and fixing them to the latter by injecting a resin material.
By this known method it is very difficult to obtain an accurate orientation of the winding wires and hence a high density packing of the letters.
Accordingly, the invention is intended to solve the problem of how to accomplish a stator for an electric machine with a maximum effective space available for the winding coil wires in relation to the total cross sectional area of the windings and at the same time obtain an accurate orientation of the winding coil wires inside the flux collector ring.